os/bluestore/BitMapAllocator: make nblks calculationg simpler and faster

Signed-off-by: xie xingguo <xie.xingguo@zte.com.cn>

diff --git a/src/os/bluestore/BitMapAllocator.cc b/src/os/bluestore/BitMapAllocator.cc
index 22cd3a5217d23406ca0f9a5a1ffc7848533e5d29..846ba6bc249a74596755bde875e78a980ceea989 100644 (file)
--- a/src/os/bluestore/BitMapAllocator.cc
+++ b/src/os/bluestore/BitMapAllocator.cc
@@ -88,8 +88,7 @@ int BitMapAllocator::allocate(
 {
 
   assert(!(alloc_unit % m_block_size));
-  int64_t len = NEXT_MULTIPLE(want_size, m_block_size);
-  int64_t nblks = len / m_block_size;
+  int64_t nblks = (want_size + m_block_size - 1) / m_block_size;
 
   assert(alloc_unit);